How do I make a PATCH request in PHP using cURL?

I have to make a PATCH request using PhP cURL. I couldn't find any documentation, so I tried the following but it isn't working.

$data = "{'field_name': 'field_value'}";
$url = "http://webservice.url";
$headers = array('X-HTTP-Method-Override: PATCH');
$curl = curl_init();
curl_setopt($curl, CURLOPT_URL, $url);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($curl, CURLOPT_POST, 1);
curl_setopt($curl, CURLOPT_POSTFIELDS, $data);
curl_setopt($curl, CURLOPT_HTTPHEADER, $headers);
$response = curl_exec($curl);
curl_close($curl);

Any idea why this isn't working? How can I fix it?

Edit: I am connecting to a RESTful web service. It returns HTTP/1.1 200 for successful requests. Unsuccessful requests return HTTP/1.1 403. I keep getting 403.

I tried changing $data to:

$data = "data={'field_name': 'field_value'}";

It didn't change the outcome.

Edit2: The final working code.

$data = "{'field_name': 'field_value'}";
$url = "http://webservice.url";
$headers = array('Content-Type: application/json');
$curl = curl_init();
curl_setopt($curl, CURLOPT_URL, $url);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($curl, CURLOPT_CUSTOMREQUEST, 'PATCH');
curl_setopt($curl, CURLOPT_POSTFIELDS, $data);
curl_setopt($curl, CURLOPT_HTTPHEADER, $headers);
$response = curl_exec($curl);
curl_close($curl);

curl_setopt($curl, CURLOPT_CUSTOMREQUEST, 'PATCH'); should do it.

JSON PATCH would be better for data format since this format is designed for HTTP PATCH request. See https://www.rfc-editor.org/rfc/rfc6902 for the spec. The tutorial of Rails 4 show the example(http://edgeguides.rubyonrails.org/upgrading_ruby_on_rails.html#http-patch).

// https://www.rfc-editor.org/rfc/rfc6902#section-4
$data = '{ "op": "add", "path": "/a/b/c", "value": "foo" }';
$headers = array('Content-Type: application/json-patch+json');

Try Using normal array

//$data = "{'field_name': 'field_value'}";

$data = array('field_name' => 'field_value' );

You can define methods and use everything in one curl function. Hope this helps you.

define('GI_HTTP_METHOD_GET', 'GET');
define('GI_HTTP_METHOD_POST', 'POST');
define('GI_HTTP_METHOD_PUT', 'PUT');
define('GI_HTTP_METHOD_PATCH', 'PATCH');

curl_setopt($ch, CURLOPT_POST, true);
if ($method === GI_HTTP_METHOD_PUT) {
	curl_setopt($ch, CURLOPT_CUSTOMREQUEST, GI_HTTP_METHOD_PUT);
}
if ($method === GI_HTTP_METHOD_PATCH) {
	curl_setopt($ch, CURLOPT_CUSTOMREQUEST, GI_HTTP_METHOD_PATCH);
}